It is known to determine the refractive indicies of bulk fluids utilizing Ellipsometry, Polarimetry, or Intensity techniques. Briefly, a beam of electromagnetism is caused to interact with a contained volume of said fluid and the resulting changes therein is monitored, said changes being related to the refractive index. Where Ellipsometry or Polarimetry are utilized, the electromagnetic beam is polarized.
A problem can develop where the fluid is a liquid at room temperature, the volume of liquid is limited and/or the container for the liquid interacts with the liquid and effects or masks desired results. Further, where a bulk liquid is contained in an open surface container, said container must be maintained in an upright position and aligned with respect to the effect of gravity, to prevent liquid spillage therefrom.
The disclosed invention recognizes the identified problem and provides a solution in the form of providing a means for presenting a liquid which makes even very thin films thereof appear as optically think films.
A Search of patents was conducted with the disclosed invention in mind, the results of which follow.
Patents cited by the Examiner during prosecution of the CoPending patent application Ser. No. 10/407,578 are:                Published Patent Application No. US2002/0003665 A1 of Mearini et al., describes depositing Diamond Like Carbon (DLC) onto a roughened surface to cause it to become functionally smooth. While use of an Ellipsometer is contemplated to monitor the process, it is noted that DLC is not a liquid, and nothing in said 665 application suggests replacing the DLC with a liquid.        Published Patent Application No. US2003/0025899 A1 of Amara et al., describes a method and apparatus for determining refractive index and thickness of thin films.        U.S. Pat. No. 6,392,756 to Li et al., which describes method and apparatus for determining physical properties of thin films deposited on a complex substrate.        U.S. Pat. No. 4,683,160 to Bloch et al., which describes solar cells with correlated roughness substrate.        U.S. Pat. No. 5,910,842 to Piwonka-Corle et al., describes a focused bean ellipsometer.        U.S. Pat. No. 6,444,898 to Fujisawa et al., describes a transparent layer product on a glass article.        
Continuing, while not obviating of the disclosed invention, probably the best prior art identified are U.S. Pat. Nos. 5,502,560 and 5,610,708 to Anderson et al., which describe apparatus comprising a diffraction grating, and methodology of its use in determining concentrations of materials in fluids. An element comprising a diffraction grating is placed into contact with a sample and a beam of polarized light is caused to pass through said element and reflect from the interface between said diffraction grating and the sample. The reflected spectrum is reported to have features related to the complex dielectric constant, which is dependent on concentrations of materials in the sample.
U.S. Pat. Nos. 5,307,105 and 5,420,680 to Isobe et al. describe apparatus and methodology for measuring refractive index and thickness of a thin film formed on a substrate.
U.S. Pat. No. 4,590,574 to Edmonds et al. describes a method for determining oxygen and carbon in a silicon substrate having a rough surface.
U.S. Pat. No. 4,514,582 to Tiedje et al. describes a system which enhances optical absorption in amorphous silicon comprising a substrate with a sandblasted surface, upon which is deposited a thin film of semiconductor.
U.S. Pat. No. 3,985,447 to Aspnes is disclosed as it describes measurement of thickness and refractive index of a thin film on a substrate.
U.S. Pat. No. 3,973,994 to Redfield describes a solar cell comprising a thin layer of active semiconductor on the surface of a transparent substrate which has grooves present in the back side thereof.
Even in view of the prior art, need exists for a method which allows measurement of bulk refractive indicies of a liquid using only a small amount thereof.